Fragmented QRS on twelve-lead electrocardiogram predicts arrhythmic events in patients with ischemic and nonischemic cardiomyopathy.

ABSTRACT

BACKGROUND: Myocardial scar is a substrate for reentrant ventricular arrhythmias and is associated with poor prognosis. Fragmented QRS (fQRS) on 12-lead ECG represents myocardial conduction delays due to myocardial scar in patients with coronary artery disease (CAD). OBJECTIVE: The purpose of this study was to determine whether fQRS is associated with increased ventricular arrhythmic event and mortality in patients with CAD and nonischemic dilated cardiomyopathy (DCM). METHODS: Arrhythmic events and mortality were studied in 361 patients (91% male, age 63.3 +/- 11.4 years, mean follow-up 16.6 +/- 10.2 months) with CAD and DCM who received an implantable cardioverter-defibrillator for primary or secondary prophylaxis. fQRS included various RSR' patterns (QRS duration <120 ms), such as > or =1 R prime or notching of the R wave or S wave present on at least two contiguous leads of those representing anterior (V(1)-V(5)), lateral (I, aVL, V(6)), or inferior (II, III, aVF) myocardial segments. RESULTS: fQRS was present in 84 (23%) patients (fQRS group) and absent in 100 (28%) patients (non-fQRS group). Wide QRS (wQRS; QRS duration > or =120 ms) was present in 177 (49%) patients. Kaplan-Meier analysis revealed that event-free survival for an arrhythmic event (implantable cardioverter-defibrillator shock or antitachycardia pacing) was significantly lower in the fQRS group than in the non-fQRS and wQRS groups (P <.001 and P <.019, respectively). fQRS was an independent predictor of an arrhythmic event but not of death. CONCLUSION: fQRS on 12-lead ECG is a predictor of arrhythmic events in patients with CAD and DCM. fQRS is associated with a significantly decreased time to first arrhythmic event compared with non-fQRS and wQRS.